Radioimmunoassays for Adriamycin and Daunomycin1

Antibodies directed toward adriamycin have been produced in rabbits, monkeys, and a goat by immunization with adriamyciniprotein conjugates. The antisera react equally well with adriamycin and daunomycin but differ in their reaction with adriamycin aglycone and other anthracycline derivatives. Radioimmunoassays, which utilize immune precipitation or nitrocellulose membrane filtration for separation of antibodybound and free antigen, were developed for adriamycin and daunomycin. The lower limit of detection is 2 pmoles of drug equivalents per ml of unextracted plasma or urine. The sensitivity of the assay is such that serological activity could be detected in human plasma several days after adriamycin was administered. The distribution of adriamycin administered to rabbits and a monkey was determined. In the monkey, adriamycin was found in the formed elements of blood at equal or greater concentrations than in the plasma. Some adriamycin remained in the blood cells even after they were washed four times with buffer. The distribution of adriamycin in the tissues of a rabbit sacrificed 24 hr after administration of the drug was also determined.